This invention relates to new and useful improvements in rotationally moulded septic tank sleeves.
Septic tanks are normally buried some two to seven feet below grade depending upon conditions and from time to time it is necessary to enter a tank to remove accumulated solids or sludge, or to service liquid level controls.
To this end, a septic tank manhole access sleeve is normally provided and formed by joining together as by bolts, screws, bonding, or the like, the appropriate number of moulded fibreglass sleeve sections, flanged at the ends thereof, in order to achieve the desired manway length. An adapter collar is then bolted or bonded to the lower end thereof and attached to the tank body over the manhole with screws or the like just prior to installing the tank into the ground after which the hole is then backfilled and tamped down.
This results in a fibreglass-lined, 24" manway protected by a moulded fibreglass lid which is attached with sheetmetal screws to the flange of the uppermost sleeve. The lid or cover may be fitted with an 8" service lid in the center thus providing a "childproof" cover system that prevents children from casually removing the main cover and falling into the tank.
This system is labour-intensive to produce and assembly. The sleeves are relatively expensive because they are produced by the hand-lay up process and hand assembled. Also in order to achieve the required strength in the fibreglass, the price is increased to a point where the product is non-competitive.
The present invention overcomes these disadvantages by providing an access sleeve produced by rotationally moulding the sleeve from a synthetic plastic such as low density polyethylene. As an example, these sleeves may be produced in a 5-foot, one-piece sleeve or, alternatively, a 5-foot, one-piece but sectional sleeve.
The moulds are designed so that a lid may be moulded on either end of the sleeve body and the lid may be cut off at a parting-off line from the finished sleeve and trimmed so that it drops down over means on the sleeve body which, in cooperation with corresponding means on the lid, may be twist-locked into position thus sealing the cover and lid securely to the body of the sleeve.
In the case of the sectional sleeve, they may be parted off at predetermined positions and assembled onto other sections to creats a variety of lengths including sections which may be added to the one-piece sleeve to create an extra-deep manway. Of importance is the sealing lip that is created when the cover is parted off from the body which ensures a tight fit between the cover and body or body sections and prevents seepage of ground water into the tank.
The cover may be fitted with an 8" service access as is conventional and screws may detachably secure the cover to the body to prevent an authorized removal thereof.
In accordance with this invention there is provided an access sleeve for septic tanks and the like comprising in combination a rotationally moulded cylindrical sleeve, a cover portion moulded integrally upon at least one end of said sleeve, an annular parting-off line formed between said cover portion and said one end of said sleeve whereby said cover can be removed after moulding, and means on said one end of said sleeve cooperating with means on said cover for detachably securing said cover to said one end in sealing relationship therewith after said cover has been parted off from said sleeve.
A further advantage of the invention is to provide access sleeves which include a moulded collar that may be trimmed to adapt same to a variety of tank sizes with the collar being secured to the tank by means of rubber bolts which are conventional in attaching plastic or fibreglass parts together.
A further advantage of the invention is to provide a device of the character herewithin described which is extremely simple in construction, economical in manufacture and otherwise well suited to the purpose for which it is designed.
With the foregoing in view, and other advantages as will become apparent to those skilled in the art to which this invention relates as this specification proceeds, the invention is herein described by reference to the accompanying drawings forming a part hereof, which includes a description of the best mode known to the applicant and of the preferred typical embodiment of the principles of the present invention, in which;